The present invention relates to circuit breakers in general, to push-push circuit breakers in particular and more particularly to a mechanical interlock for preventing operation of one push-push circuit breaker upon operation of another.
The push-push circuit breaker of the type with which the present invention is principally adapted for use is described in U.S. Pat. No. 3,075,058 issued to Elwood T. Platz and Victor Mitchnick on Jan. 23, 1963, entitled "Push-Push Circuit Breaker", and assigned to the assignee hereof. That patent is incorporated herein by reference for its teaching of the design and operation of such circuit breakers. The circuit breaker is manually operated from the "on" or contacts engaged position to the "off" or contacts separated condition by depressing toward the circuit breaker casing a depressible push button handle which normally projects from the top side of the circuit breaker. Operation of the circuit breaker from "on" to "off" could be prevented by means which blocks depressing of the push-push button or handle. In such a circuit breaker, both of the line and the load terminals are usually located on the same, front side of the circuit breaker. The rear side of the circuit breaker has no circuit breaker operating elements projecting from or located on it. It has, therefore, become usual to pair two such circuit breakers back to back with their rear sides facing toward each other and spaced apart a short distance and to provide a common cap for both operating handles, which cap bridges the gap between the paired circuit breakers and operates their handles together.
In typical panelboard installations, it is usual to gang the circuit breaker pairs in a row with the sides of the casings of the circuit breakers in adjacent circuit breaker pairs contacting.
In certain installations, when one push-push circuit breaker is "on", it is desirable that at least some of the other circuit breakers in the installation be prevented from being operated "on". When that first circuit breaker is operated from "on" to "off", then those circuit breakers that had been disabled from being operable "on" should thereafter be operable "on".